1. Field of the Invention
The present invention relates to a fuel cell formed by stacking membrane electrode assemblies and separators. Each of the membrane electrode assemblies includes a pair of electrodes and an electrolyte membrane interposed between the electrodes. Further, the present invention relates to an apparatus for producing such a fuel cell.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell employs a solid polymer electrolyte membrane. The solid polymer electrolyte membrane is a polymer ion exchange membrane. In the fuel cell, the solid polymer electrolyte membrane is interposed between an anode and a cathode to form a membrane electrode assembly (electrolyte electrode assembly) (MEA). The anode and the cathode each includes an electrolyte catalyst layer and porous carbon. The membrane electrode assembly is sandwiched between separators (bipolar plates) to form a unit cell. In use, generally, a predetermined number of unit cells are stacked together to form a fuel cell stack, which is mounted in a vehicle, for example.
The separators include an anode side separator having a fuel gas flow field facing the anode for allowing a fuel gas to flow along the anode, and a cathode side separator having an oxygen-containing gas flow field facing the cathode for allowing an oxygen-containing gas to flow along the cathode. The anode side separator and the cathode side separator overlap each other to form a coolant flow field for allowing a coolant to flow along the anode side separator and the cathode side separator.
Therefore, in particular, in the case of producing a fuel cell stack mounted in a vehicle, a considerably large number of membrane electrode assemblies, anode side separators, and cathode side separators need to be prepared individually. Thus, operations for handling such parts are complicated, assembly performance of the fuel cell stack is low, and the fuel cell stack cannot be produced efficiently.
In this regard, for example, a fuel cell disclosed in Japanese Laid-Open Patent Publication No. 2009-176490 is known. As shown in FIG. 13, such a fuel cell includes a first separator plate 2 and a second separator plate 4. The first separator plate 2, which is made of a porous material, has a fuel gas flow field 1 for supplying a fuel gas to a fuel electrode. The second separator plate 4, which also is made of a porous material, has an oxygen-containing gas flow field 3 for supplying an oxygen-containing gas to an oxygen-containing gas electrode.
The first separator plate 2 and the second separator plate 4 are attached together to form a coolant water flow field 5 between the first separator plate 2 and the second separator plate 4. An adhesive sheet 6 is attached to side surfaces of the first separator plate 2 and the second separator plate 4. An adhesive is not applied to surfaces where the first separator plate 2 and the second separator plate 4 are attached together.
Thus, according to the disclosure, when water in the coolant water flow field 5 moves from the fuel gas flow field 1 to the oxygen-containing gas flow field 3, a water repellent adhesive does not prevent movement of water.